There isn't- Macrophthalmus was discredited as a separate species as it was decided that it was the same as Aimara.
It was originally described in 1846 as Aimara then redescribed in 1907. Some work was done that suggested that the two fish were Identical so the oldername takes presedence.
Just to confuse matters further Curupira is sometimes sold as Macrophtalmus.
Just to confuse matters further Curupira is sometimes sold as Macrophtalmus.
And what is your opinion for the fish in the above photo??
http://www.amazon-exotic-import.de/Gallerie/Salmler/Seiten/Hoplias macrophtalmus.htm
here's the link see it better